Reinforcer for telephone-circuits.



. ALEXANDERBON.

REINFORGER FOR TELEPHONE CIRCUITS.

ELF-W APPLICATION FILED JAN.6,1910.

Patentad June 2'2,-

W'IZYESSEEI nirrrr: er

ERNST F. W. #LEXANDERSON, OF SCHENEGTADY, IIEW' YORK, ASSIGNOE, TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YURI L nniuroncnn ron TELEPHONE-CIRCUITS.

10 on w/wm it may concern: I I

I Be It known that I, Enns'r F. W. Amie linonnson, a citizen of the United States, re-

siding at Schenectady, county of Schenectady, State ofNeW York, have invented certoin new and usefullmprovements 1n Rem- Iorcers for TlGPl10l1-O1I'Cl1ltS, of Which the following is a specification.

My invention relates to reinforcing means for the currents in telephone c1rcn1ts,ond its object is to provide a simple and etlici'ent (le- My invention consists in the combination with a telephone circuit, of va reinforcer comprising an alternating current dynamo- 1 electric machine having-its field circuit contore circuit tuned approximately to reso-. nonee. This may, be accomplished by con-c necting the armature me local closed circuit nected to the telephone circuit and its urine,-

conteining a proper amount of capacity.

The principle of the device depends upon .the feet that any alternating current gen:

orator having a small initial field magnetization may he brought up to full field strength Without eny field Winding if the armature is connected to osuiteole condenser so that the armature recetlonof the condenser current Inegnefiizes the field. If the generator could be conceived ilS-WltllOllt satuintion, the field strength produced in this 'Waywould rise indefinitely, If the condenser is tun'eclso that the circuit is approximately at; resonance, the field strength Will be proportional to the original or residual magnetism but many times as great. N ow if a machine with the armature circuit thus tuned by 21 condenser has its field circuit connected to the telephone circuit, the Voltage in the tele phonecircuit, due to the telephone current,,

will be impressed upon the field circuit of the machine, producing therein the initial magnetization This'is increased by arrow ture reaction many fold, and the increase in field on reacts inductively upon the field circuit. The result is that the electro-inotivc force returned by the generator field to the telephone circuit is nizlnytimes greater than the electro-motive force originally, im-

pressed upon the held from that circuit.

Thg alternating currents flowing in the high Specification of Letters latent.

Patented frequency armature circuits and the condensers have nothing to do with the telephone currcnhexcept that their armature reaction amplifies the field strength, and so, indirectly amplifies the telephone current. i I ,My invention will best be understood by reference to the ecconipanying drawings, in which Figure 1 shows diagrammatically the general case of an alternator used, in accordance Wllhhly invention, use reinforeer for a telephone circuit; Fig. 2 shows diagrammatically the connections when the preferred form of alternator is employed; Fig. 3 shows elevation in cross-section of the upper halt of on alternator of preferred construction for this use, and Fig. l is on explnnatory detail View. In Fig. l, A represents a telephone circuit:

containing, the usual transmitter B, source of;

upon it by the telephone circuit A, as has already been explained, and the telephone currents are accordingly increased in intensity lwithout tneirrreve shapes being affected.

in Fig. 2 have indicated liagrom1,m1ti cally the connections of oprefcrred; form of alternator, This machine the same as thatldesci'ihed in my prior application, Sc-

' rial No. 521,352, vtiled November ll, 190$),in

which a single winding ll is common to both the lield and armature circuits. This machine hus two advantages as a telephone reinforcer when compared Wth other mu- 7 chines, first, there is no magnetic leakage between the armature and field circuits, since a single Winding and its connections dorm both circuits; second, the niocl'line is of a type which can be constructed with almost no residual magnetism which is an advantage in telephone were. This is due to the arrangement of the magnetic circuit or" the machine which is such that the field flux is June 2'27, H911.

local closed" not constant, as in the ordinary inductor alternator, but varies with the movement of the inductor.

The construction of the machine is shown in Figs. 3 and t, in which K represents the stator frame carrying two concentric lami-' nated magnetic rings L. The coils of the winding H areplaced in slots in the opposite faces of these rings, as is best shown in Fig. 4. The inductor I carries at its periphery, between the rings L, laminated pole pieces 2' separated by blocks z" of non-magnetic material. When the poles i-are opposite the coils H, as shodn in Fig. 4, the path of the field flux is of comphratively low re luctance, but when the poles are midway;

between two adjacent coils the reluctance of the path of the field flux is very great. The movement of thepoles of the inductor, by varying the reluctance of the flux path, varies the flux and, consequently, induces an electro-motive force in the same coils H which produce the flux. This induced voltage, which may be termed the armature voltage, is impressed on the condensers suitably connected in a local closed circuit with v the winding H so as to obtain the. armature reaction intensifying the volt-ageof the field circuit, as heretofore explained.

The connections for the armature and field circuits are shown in Fig. 2. The field circuit comprises all the coils of winding H but the halves of this winding are so connected that the voltages induced in them by the movement of the inductor are in opposition with respect to the field circuit. This is indicated by the arrows placed adjacent.

the winding H in Fig. 2. The armature voltage produced by the movement of the lnductor, therefore, has no direct effect whatever on the field circuit The armature circuit is led off from the point at the middle of the winding H and from a point at the middle of a reactance J connected across the terminals of the neid circuit. These points are thus equi-potential with respect to the field terminal voltage but are at the points of maximum voltage with 'respeet to theinduced armature voltage, as will be seen by inspecting the directions of the arrows. The two halves of the winding H are in parallel in the armature circuit, which is closed through the condenser G which is properly adjusted for tuningthe' armature circuits approximately to resofl nance. The reaction of the armature on the field circuit and the reinforcing of tlieate'lea phone currents thereby are precisely the same as has been explained in connection with Fig. 1.

I do not desire to limit myself to the par,- ticular construction and 'rangement of parts shown and described, ut aim in the appended claims to cover all "modifications to its field and armature circuits, the field circuit being connectedto the telephone circuit and the armature circuit being a local closed circuit containing capacity.

In witness whereof,--I have hereunto set my hand this 5th day of January, 1910.

ERNST F. W. ALEXANDERSON.

' lVitnesses':

BENJAMIN B. HULL,

HELEN Onronn. 

